Torsion Rod Research Articles

Experimental assessment of the eigenstress state in two-ply yarns and its effect on tensile properties

Propaedeutical to a better understanding of the mechanics of cables, with potential applications in material science and biology, tensile tests were performed on two-ply yarns made of rubber rods, manufactured by transforming the twist on two adjacent straight rods into tortuosity for the resulting double-helix shape. Modeling of the yarn as a pair of Kirchhoff rods in reciprocal contact, fails to provide results in agreement with experiments, especially when the helix slope angle α tends to π/4, representing the geometric limit for material interpenetration. This discrepancy could not be justified by considering the viscosity of the rods, their cross-sectional distortion, or cohesive/frictional contact. Our contribution starts from the experimental observation that the rods are in an eigenstress state already in the reference balanced configuration. This is characterized by a high twist, dictated by the ratio between torsional and bending rod stiffness, which increases as α decreases, growing unboundedly as α→π/4. Experiments confirm that twisting can significantly increase the tensile stiffness of straight rubber rods, in agreement with non-linear elasticity theory. Tensile tests on the yarns can be reproduced excellently only if the twist-induced stiffening is considered.

A novel nonlinear oscillator consisting torsional springs and rigid rods

In this paper, we propose an archetypal double-winged novel nonlinear oscillator composed of torsional springs and rigid rods which behaves smooth and discontinuous dynamics and a kind of special collision pendulum depending on the varying of a geometrical parameter. The system behaves complicated equilibrium bifurcations with different geometrical states, leading to a series of buckling phenomenon and the loss of uniqueness near the limit points. A ‘collision’ parameter is introduced to determine the motions near the limit points which causes a discontinuous jump of velocity and exhibits the standard dynamics as an inverted pendulum, even though the mechanic model is rather different from a pendulum. We also distinguish the coexistence of periodic and chaotic motions and also a smooth period 1 located in a small region under the presence of damping and external force using amplitude–frequency analysis and numerical simulations. This research enriches the complicated dynamical behaviors of geometrical nonlinear oscillator and provide a novel structure which is of great potential in vibration isolation engineering.

Deformation and Shear Stress Analysis of Torsional Rod Used in Automobile in Various Materials Using Solidworks and Ansys: A Review

Abstract: Deformation and shear stress analysis are pivotal considerations in the design and performance evaluation of mechanical components, particularly in the automobile industry. The behaviour of torsional rods, critical load-bearing elements in many automotive systems, necessitates meticulous assessment to ensure optimal functionality and longevity. This review delves into the comprehensive study of deformation and shear stress analysis of torsional rods employed in automobiles. The investigation harnesses the capabilities of two industry-standard simulation tools, SolidWorks and ANSYS, to explore a spectrum of materials commonly used in automotive engineering. The juxtaposition of SolidWorks and ANSYS serves as a comprehensive approach to examining the behaviour of torsional rods across various materials, offering valuable insights for both researchers and practitioners. Through illustrative case studies and comparative analyses, this review sheds light on the unique attributes of different materials and simulation platforms, contributing to the advancement of automotive component design and analysis methodologies. Based on previous research the objective of this review paper is “Deformation and Static Stress Analysis of Torsional Rod Using Various Materials” Based on previous research the objective of this review paper is “Deformation and Shear Stress Analysis of Torsional Rod Using Various Materials”

Towards closed-walled designs in topology optimization using selective penalization

3D topology optimization using a density approach with penalization usually produces truss-like, open-walled structures. The coarser the mesh, the smaller the volume fraction, and the faster the penalization is increased, the more pronounced this effect tends to be. However, closed-walled designs are often more efficient and have other beneficial properties. For instance, closed walls can contribute to achieving self-supporting designs for additive manufacturing that potentially require fewer sacrificial support structures than truss-like designs. This paper presents a two-step optimization procedure for generating closed-walled designs using coarse meshes. The first step takes the usual Eulerian approach of performing a SIMP-based topology optimization on a fixed mesh. To keep thin geometrical features, like walls with a thickness below element size, penalization is switched off deliberately where the formation of such features is detected. Adopting a Lagrangian description, intermediate densities still present in the optimized design are subsequently eliminated in a second step by shrinking each element according to its density. By analogy with volumetric thermal contraction, this is accomplished by solving a fictitious thermo-elastic problem where the temperature has been replaced by a density expression. The outcome is a morphed mesh with a somewhat smoothed surface and a volume close to the specified material volume limit. This body-fitted representation of the design considerably simplifies the final conversion into a manufacturable CAD-type geometry. The two-step optimization procedure is applied to a cantilever, a torsion rod, and a disk reinforcement benchmark problem. Optimized designs are closed-walled and show very good agreement to those found for much finer meshes. Problem-specific stiffness improvements over truss-like designs between 6% and almost 30% were achieved and confirmed the findings previously reported by other authors.

Properties of torsion rod in "Sulzer” projectiles loom

The torsion rod characteristics of the Sulzer loom can be adjusted in the zero position by means of the adjusting lever and the adjusting actuator of the torsion rod of loom. In the "Sulzer" projectile loom, the movement of the intermediate member results in the axial movement of the adjusting lever to change the position of the zero according the material and characteristics of rod. The intermediate member transmits a force exerted by the adjusting lever to a fixed sliding surface. However, the described device in some countries has a serious drawback, because the tuning drive acts on the torsion rod adjusting lever so that when the projectile is fired into the “Sulzer” loom, the picking mechanism reacts through the sudden, harmful pressure of the tuning drive. A solid wedge-shaped idler that can be moved by the adjusting motor is placed between the sliding surface of the adjusting lever and a fixed sliding surface. In the "Sulzer" projectile loom, known torsion rod control enables projectile loom operation with improved energy consumption and reduced wear.

On the torsional and coupled torsion-tension/compression behavior of magnesium alloy solid rod: A crystal plasticity evaluation

Extensive attention has been paid to magnesium (Mg) alloys considering their potential as lightweight structural materials. However, it is still challenging to process and manufacture Mg materials that carry high strength and good ductility. This issue mainly arises from a lack of understanding toward the anisotropic mechanical behavior of Mg alloys in response to large deformation in a multiaxial stress state, which is unavoidably in existence under various material processing routes. In this regard, we seek to understand the torsional and coupled torsion-tension/compression behaviors of a magnesium alloy subject to large-strain deformation. The elastic viscoplastic self-consistent (EVPSC) model, which incorporates the twinning-detwinning (TDT) scheme and takes a torsion-specific finite element (TFE) approach, was employed to illuminate the inhomogeneous and multiaxial features of the torsional deformation in the AZ31 Mg alloy subjected to free/fixed-end torsion and coupled torsion-tension/compression. Experimental validation was conducted by characterizing the mechanical responses of the torsional specimens under the loading paths of free-end torsion and coupled torsion-tension. Our model successfully captures the Swift effect along with the shear texture, which is hardly predicted by conventional constitutive models. In addition, our model reveals that twinning is nearly equally active under free-/fixed-end torsion, while twinning under coupled torsion-tension and torsion-compression is promoted and suppressed, respectively. The comparison between the simple shear and pure torsion by simulation demonstrates that the significant bulk stress existing within the torsional rod is ascribed to the strong interaction between the cylindrical elements in the EVPSC model. As a final thought, we believe that the TFE-EVPSC-TDT model not only highlights the inhomogeneous and multiaxial features underlying the torsional and coupled torsion-tension/compression behaviors of the Mg alloy solid rod, but more significantly, can be used as a numerical tool for designing/tuning gradient twinning structures that may lead to optimized properties of Mg alloys.

Применение оптоволоконной оптической системы для контроля крутящего момента вала

The article considers the procedure of torque control, which is very popular in a wide variety of industries with many design features. In marine power engineering the problems of determining the forces, torque on the shaft and power are solved by means of torsiometers with torque sensors. The most widely used torque sensors are of capacitive, induction, strain gauge and photoelectric types. It has been stated that there are limitations in the process of torque control due to the susceptibility of systems to the electromagnetic interference, lack of a high degree of protection for electrical equipment and necessary recalibration. Fiber optic systems have found application in torque measurement systems in the oil and gas and aerospace industries. The use of such systems on ships is more expensive in comparison with the technologies used today, for example, the systems based on strain gauges. It has been proposed to use an inexpensive optical measuring system based on the Pound-Drever-Hall technique with using a foil-clad strain gauge and an aluminum torsion rod. There has been illustrated the system of torque control, the phase graphs for the Fabry-Perot resonator and the graph of the resonator transmission spectrum are presented, the reflection coefficient value is given. A method for measuring the phase of a reflected beam from a Fabry-Perot resonator is being considered, the injection current of a laser is modulated by means of an electric oscillator to generate side stripes in the electric field of a laser beam. The carried out studies and calculations contribute to improving the reliability of the coastal power system; the possibility of their use in marine electrical systems has been proved.

Damped Tailgate System Drop Dynamics and Evaluation of Strut Force for Durability

<div class="section abstract"><div class="htmlview paragraph">This paper describes a simplified CAE simulation for the calculation of peak strut force in a damped tailgate system. Tailgate systems in the past included a torsion rod for lift assist, but did not include damping in the opening/drop direction. Newer tailgate systems include a strut to provide damping during drop and possibly lift assist. These tailgates may also be designed to experience a free-fall for a few degrees after being unlatched and before the strut engages. When the latch is released, the tailgate accelerates as it falls freely and then encounters a rapidly increasing damping force as the strut engages. The deceleration of the gate depends upon the damping force, yet the damping force depends upon the deceleration of the tailgate, making a precise calculation of the damping force difficult. Damping characteristics of the strut depend on the volume, the viscosity of oil and its flow restrictions across the piston. These parameters are not known early in the design process.</div><div class="htmlview paragraph">This study presents a method to back calculate the damping force on a tailgate solely based on the desired drop time, and does not require physical measurements of the strut. An ABAQUS explicit analysis with beams and connectors is defined to simulate the tailgate drop event. The simulation calculates the damping force, based on a linear damping coefficient and the velocity of the strut at each incremental drop position. Peak strut force is found to occur mid-way through the drop event and is greater than the force of the fully compressed strut. The simulation shows good correlation to measured time history for strut force, tailgate drop angle and strut linear motion.</div></div>

Design and Research of a Model of a Pair Active Aircraft Control Sidesticks Operation in MATLAB

Development of an aircraft active sidestick control is an actual direction in modern flight control systems which allows to increase safety, to improve cabin ergonomics and to reduce the mass and weight of control levers. The article devoted to simulation modeling of a pair active sidesticks based on electromechanical actuators coupled by a frameless kinematic scheme, providing identical dynamic characteristics for the pitch and roll channels. MATLAB, Simulink, Simscape, with SimMechanics and SimPowerSystems libraries was used to create the mathematical model. Parameters such as moments of inertia was count based on the 3D model of the active sidestick. The complex model includes two active sidesticks units, three blocks as the input source ("Autopilot", blocks of the 1st and 2nd pilots), a block that compute a loading characteristic for the manual control mode and a block with logic for switching from automatic to manual mode. The model of each active sidestick unit consists of three main blocks: a regulator, an electric motor with a control system, and a block of mechanics. The regulator block includes a PID regulator and a PWM modulator. The electric motor unit includes a power source, a three-phase bridge inverter, a model of a brushless three-phase electric motor from the SimPowerSystems library and a power switch control unit. The mechanics block includes a planetary gearbox, hinge mechanism, handle, moments of inertia, a position sensor, a torsion rod equal to tension springs which are used in device, a nonlinear speed damper and a torque source unit, depending on the force applied by the pilot. Developed model makes it possible to get static and dynamic characteristics of the actuators, to check control algorithms to simulate operating modes in automatic and manual control, including piloting by both pilots at the same time and the interruption in automatic control mode. Including in model a " hold position block" allowed to simulate situation when in manual control mode the 1st pilot tries to hold the handle in a position that he considers correct, despite the intervention of the 2nd pilot. The simulation results showed that developed device meets specified requirements for the aircraft active sidesticks.

Inhomogeneous Rods in Torsion: Longitudinal Fracture Analysis by Considering the Energy Balance

Fracture of inhomogeneous non-linear elastic rods with a longitudinal circular cylindrical crack is analyzed. Rods have circular cross-section and are loaded in torsion. General approach for analyzing the strain energy release rate is developed by considering the balance of the energy. The rods exhibit continuous material inhomogeneity in both radial and length directions. The general approach is applied to analyze the strain energy release rate for a longitudinal crack in a clamped inhomogeneous rod loaded in torsion. The strain energy release rate is derived also by considering the complementary strain energy for verification.

Torsional Vibration and Bifurcation Characteristics of Automotive Main Reducer Based on Nonlinear Hybrid Model

In the view of integrating dynamics of systems with dynamics of structures, the pinion shaft of automobile main reducer is divided into several torsion rod elements to establish its dynamic model, while the torsional vibration dynamic model of hypoid gears is still built with lumped mass method, thus the hybrid dynamic model of automotive main reducer is obtained by the combination of two kinds of dynamic models. Considering the nonlinear factors such as time-varying mesh stiffness, backlash and static transmission error of gear pairs, Runge-Kutta method is applied to obtain the time domain spectrum, spectrum graph, phase-plane diagram, Poincaré maps, and bifurcation diagrams of the system. The dynamic response characteristics of system with different parameters such as input rotational speed and mesh stiffness are systematically investigated by numerical simulations.

Snap‐Through and Mechanical Strain Analysis of a MEMS Bistable Vibration Energy Harvester

Vibration‐based energy harvesting via microelectromechanical system‐ (MEMS‐) scale devices presents numerous challenges due to difficulties in maximizing power output at low driving frequencies. This work investigates the performance of a uniquely designed microscale bistable vibration energy harvester featuring a central buckled beam coated with a piezoelectric layer. In this design, the central beam is pinned at its midpoint by using a torsional rod, which in turn is connected to two cantilever arms designed to induce bistable motion of the central buckled beam. The ability to induce switching between stable states is a critical strategy for boosting power output of MEMS. This study presents the formulation of a model to analyze the static and dynamic behaviors of the coupled structure, with a focus on the evolution of elongation strain within the piezoelectric layer. Cases of various initial buckling stress levels, driving frequencies, and driving amplitude were considered to identify regimes of viable energy harvesting. Results showed that bistable‐state switching, or snap‐through motion of the buckled beam, produced a significant increase in power production potential over a range of driving frequencies. These results indicate that optimal vibration scavenging requires an approach that balances the initial buckling stress level with the expected range of driving frequencies for a particular environment.

Modeling and performance analysis of a vehicle with kinetic dynamic suspension system

This paper presents a kinetic dynamic suspension (KDS) system to achieve enhanced cooperative control of the roll and warp motion modes for on-road and off-road sports utility vehicles (SUV). The proposed KDS system consists of two hydraulic circuits acting on two pairs of torsional rods and levers, which can be treated as novel anti-roll bars. Hence, these anti-roll bars do not work independently, but are coupled to merely respond to particular motion modes. To verify the handling and ride performance of the system, a 14-DOF model of a SUV and a “magic formula” tire model are developed. The dynamic responses of the vehicle model with KDS suspension are obtained through half-sine bump, asynchronous sine road, and fishhook maneuver simulations. The responses of the KDS equipped vehicle are compared to those of one with anti-roll bars to demonstrate its improved performance and also illustrate the side-effects. The results show that the KDS system considerably improves the vehicle’s anti-roll ability. Furthermore, the vehicle’s warp stiffness is significantly reduced by the KDS system, which enhances the vertical load distribution of each wheel when driving off-road.

Y25 freight car bogie models properties analysis by means of computer simulations

The article deals with the results of the simulation analysis of a railway wagon bogie model. We analysed four freight wagon bogie variants for its dynamics properties research. The bogie models correspond in general to the Y25 bogie concept. The models were created in SIMPACK software enhanced by the RAIL module. From the research results depicted in the graphs we found out, that the newly designed bogie variant gives the best results when compared to the other analysed versions. The newly designed model consists of a standard Y25 bogie frame with two Lenoire friction dampers. This bogie is equipped with longitudinal linkages on both sides. These linkages are completed with a radial torsion binding, torsion rod, between side bogie parts. The contact of railway wheels and rails generates active forces affecting the surface contact, affecting the size of the normal and tangential stress, wear surfaces of the wheel/rail, or directly the size of the derailment.

Annealing behavior of gradient structured copper and its effect on mechanical properties

In this study, hot-extruded copper rods were subjected to free-end-torsion and subsequent annealing. The microstructures and mechanical properties of the deformed samples and annealed samples were investigated. The results show that torsion can introduce gradient lamellar dislocation substructures (LDS) into the copper rods, suggesting a gradient distribution of stored energy from core to surface. Different degrees of recrystallization were formed in the same torsional rod after recrystallization annealing due to such gradient stored energy. Annealing can change the microstructure inversely from deformed gradient into annealed gradient distribution via fully recrystallization in the surface layer and incomplete recrystallization in the middle layer. Therefore, gradient structured copper rods with soft core and hard shell or hard core and soft shell could be obtained by torsion or the combination of torsion and subsequent annealing, respectively. The tensile yield strength of such gradient structured rods has a linear relationship with the volume fraction of hard and soft regions no matter where the hard region is located, core or surface. The incomplete recrystallization mechanisms of gradient structured copper rods induced by torsion were also discussed.

A Biologically Inspired Knee Actuator for a KAFO

Knee–ankle–foot orthoses (KAFOs) are prescribed to improve abnormal ambulation caused by quadriceps weakness. There are three major types of KAFOs: passive KAFOs, semidynamic KAFOs, and dynamic KAFOs. Dynamic KAFOs are the only type that enables to control knee motions throughout the entire walking gait cycle. However, those available in the market are heavy, bulky, and have limited functionality. The UT dynamic KAFO is developed to allow knee flexion and assist knee extension over the gait cycle by using a superelastic nitinol actuator, which has the potential to reduce volume and weight and reproduce normal knee behavior. In order to match the normal knee stiffness profile, the dynamic actuator consists of two actuating parts that work in the stance and swing phases, respectively. Each actuating part combines a superelastic torsional rod and a torsional spring in parallel. Geometries of the two superelastic rods were determined by matlab-based numerical simulations. The simulation response of the dynamic actuator was compared with the normal knee stiffness, verifying that the proposed design is able to mimic the normal knee performance. The surrounding parts of the dynamic knee joint have then been designed and modeled to house the two actuating parts. The dynamic knee joint was fabricated and mounted on a conventional passive KAFO, replacing its original knee joint on the lateral side. Motion analysis tests were conducted on a healthy subject to evaluate the feasibility of the UT dynamic KAFO. The results indicate that the UT dynamic KAFO allows knee flexion during the swing phase of gait and provides knee motion close to normal.

Freight Car Bogie Properties Analysis by Means of Simulation Computations

The article deals with the results of the simulation analysis of a railway wagon bogie model. We analysed four freight wagon bogie variants for its dynamics properties research. The bogie models correspond in general to the Y25 bogie concept. The models were created in SIMPACK software enhanced by the RAIL module. From the research results depicted in the graphs we found out, that the newly designed bogie variant gives the best results when compared to the other analysed versions. The newly designed model consists of a standard Y25 bogie frame with two Lenoire friction dampers. This bogie is equipped with longitudinal linkages on both sides. These linkages are completed with a radial torsion binding, torsion rod, between side bogie parts. The contact of railway wheels and rails generates active forces affecting the surface contact, affecting the size of the normal and tangential stress, wear surfaces of the wheel/rail, or directly the size of the derailment.

Microstructures and Mechanical Properties of Commercial Hot‐Extruded Copper Processed by Torsion Deformation

Free‐end torsion deformation is used for processing copper rod in this work. Both microstructures and mechanical properties of the torsional rods are quantitatively analyzed. The results show that gradient lamellar dislocation substructures (LDS) along the radial direction as the main defects are formed after torsion. The increment of the LDS density, the shrinking of spacing size, and the change of length/spacing (L/S) ratio of the LDS are all non‐monotonic function of torsion revolution. High‐density LDS with fine spacing can retain strain hardening capability, which results in good combination of high tensile strength and good ductility in the torsional deformed sample with large number of revolutions. The influence of torsion strain on primary twin boundaries (TBs) in the hot‐extruded rod is also discussed.

No Effect of Steady Rotation on Solid $$^4$$ 4 He in a Torsional Oscillator

We have measured the response of a torsional oscillator containing polycrystalline hcp solid $^{4}$He to applied steady rotation in an attempt to verify the observations of several other groups that were initially interpreted as evidence for macroscopic quantum effects. The geometry of the cell was that of a simple annulus, with a fill line of relatively narrow diameter in the centre of the torsion rod. Varying the angular velocity of rotation up to 2\,rad\,s$^{-1}$ showed that there were no step-like features in the resonant frequency or dissipation of the oscillator and no history dependence, even though we achieved the sensitivity required to detect the various effects seen in earlier experiments on other rotating cryostats. All small changes during rotation were consistent with those occurring with an empty cell. We thus observed no effects on the samples of solid $^4$He attributable to steady rotation.

Optimum design of mounting components of a mass property measurement system

Measurement of inertia properties of aerospace vehicle and submarine are vital to meet the intended motion objectives. The Moment of Inertia (MOI) is calculated by measuring the frequency of free torsional oscillation of the object mounted on a nearly friction less air bearing. For getting accurate measurement and to nullify the effect of undesired vibrations, the stiffness of the different components of the mounting and fixture (torsion rod, flexure) should be maintained appropriately. The optimum design of torsion rod and flexure is based on ensuring desired natural frequencies in different modes. Initiating with an analytical approach, the actual dimensions of the components are determined based on natural frequencies obtained by finite element analysis of the components. Simulated results are verified with experimental results.